References of "Portetelle, Daniel"
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See detailBiomass hydrolyzing enzymes identified by functional screening of a metagenomic library from algal biofilms.
Martin, Marjolaine ULg; Biver, Sophie ULg; Barbeyron, Tristan et al

Poster (2013, June)

Biomass hydrolyzing enzymes are increasingly searched for the production of biofuels and renewable chemical compounds using biomass. Microorganisms living on algaes are an interesting reservoir of biomass ... [more ▼]

Biomass hydrolyzing enzymes are increasingly searched for the production of biofuels and renewable chemical compounds using biomass. Microorganisms living on algaes are an interesting reservoir of biomass hydrolyzing enzymes, as they are in constant interaction with algal biomass. Therefore, we are interested in looking for some of those enzymes synthesized by the microflora living on the surface of the brown algae Ascophyllum nodosum. Algae samples were collected in the winter 2012 and a microbial DNA extraction method was developed. The whole extracted microbial genomes of the microorganisms living on the algae were restricted, inserted in a cloning vector and ligated products were used for transformation of cultivable Escherichia coli host cells. This metagenomic library was then screened for diverse enzymatic activities (lipolytic enzymes, cellulases, beta-glucosidases, alpha-amylases, arabinanases, xylanases and proteases) on agar plates with specific substrates. Five putative lipolytic enzymes, one cellulase and one beta-glucosidase were identified. Sequence analysis revealed low (<50%) sequence identities with known enzymes sequences, meaning new enzymes from unknown genomes have been discovered. To our knowledge this is the first functional screening that was realized with a metagenomic library from algal biofilms and this is the first cellulase identified by marine metagenomics. A second library has been constructed from algae sample from summer 2012 and is currently being screened. New enzymatic tests are being developed for the identification of enzymes degrading specific algal polysaccharides like agarases, carrageenases, alginate lyases, laminarinases,… Those very specific enzymes aren’t well known yet, and our metagenomic approach will probably help us to identify new families and structures of those algal biomass hydrolyzing enzymes. [less ▲]

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See detailMicroorganisms living on algae : An interesting reservoir of enzymes hydrolyzing algal biomass
Martin, Marjolaine ULg; Biver, Sophie ULg; Barbeyron, Tristan et al

Poster (2013, April 18)

Algal polysaccharides are increasingly used in food industry for their gelling properties and in pharmacology for their therapeutic properties. Furthermore, increasingly interest is taken on algae for ... [more ▼]

Algal polysaccharides are increasingly used in food industry for their gelling properties and in pharmacology for their therapeutic properties. Furthermore, increasingly interest is taken on algae for their use in the production of biofuels and bioenergies. To purify algal polysaccharides and degrade algal biomass, specific microbial enzymes are needed. Microorganisms living on algae are an interesting source of those enzymes, as they are in constant interaction with algal biomass. The aim of our study is to identify new enzymes degrading algae, produced by microorganisms living on the surface of algae. Therefore we developed a method for microbial DNA extraction from biofilms living on brown algae (Ascophyllum nodosum). Microbial DNA was extracted, restricted and inserted in cultivable host cells of Echerichia coli, for the construction of our metagenomic DNA library. This metagenomic library was first screened, on solid media with specific substrates, for enzymes generally used in the degradation of biomass (lipases, cellulases, proteases, beta-glucosidases, alpha-amylases, arabinanases and xylanases). Five lipolytic enzymes, one beta-glucosidase and one cellulase were identified. Those enzymes show very low percentages of sequences identities with known enzymes, meaning we identified new and unknown enzymes. Those enzymes and their activity are being characterized. Preliminary tests show interesting results, like a cellulase active at low temperature. Screening tests are now being developed to identify enzymes hydrolyzing algal polysaccharides like agarases, carrageenases, alginate lyases, laminarinases,… Those enzymes aren’t well known yet and we hope to identify new enzymes (families) with our rich DNA library by our approach. [less ▲]

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See detailFunctional screening of a metagenomic library from algal biofilms
Martin, Marjolaine ULg; Barbeyron, Tristan; Michel, Gurvan et al

in Smagghe, Guy; Boeckx, Pascal; Bossier, Peter (Eds.) et al Communications in Agricultural and Applied Biological Sciences (2013, February 08)

Macroalgae, and particularly their lignin-free polysaccharides, are increasingly used for their gelling and therapeutic properties and for the production of biofuels and renewable chemical compounds. To ... [more ▼]

Macroalgae, and particularly their lignin-free polysaccharides, are increasingly used for their gelling and therapeutic properties and for the production of biofuels and renewable chemical compounds. To extract, hydrolyze and purify this biomass, algae hydrolyzing enzymes are needed. Our work aims to identify and characterize algal biomass hydrolyzing enzymes expressed by microorganisms living on the surface of algae, by functional metagenomics. Therefore, a microbial DNA extraction method was developed to isolate the gDNA from the microorganisms of the brown algae Ascophyllum nodosum and a metagenomic library was constructed in Escherichia coli. The library was screened for diverse enzymatic activities (esterases, xylanases, cellulases, α-amylases, arabinanases, caseinases and β-glucosidases) on agar plates with specific enzymes substrates. Several new microbial enzymes (esterases, β-glucosidases, α-amylases and cellulases) were identified revealing the wealth of our library. Furthermore, those enzymes had less than 50% sequence identity with known protein sequences; meaning that our approach allows to identify new microbial enzymes expressed by uncultured microorganisms. Plate tests for medium-throughput screening of specific enzymes hydrolyzing algal polysaccharides (agarases, carrageenases and alginate lyases) are currently being developed. Our approach will probably allow us to identify new families of those ill-known enzymes, with particular enzymatic activities. [less ▲]

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See detailImpact of the depth on bacterial diversity in an agricultural soil
Stroobants, Aurore ULg; Degrune, Florine ULg; Lambert, Christophe et al

Poster (2013, February 08)

Bacteria are the most abundant and diverse microorganisms in soils. They play an important role in soil formation, contribute to plant nutrition and are involved in various processes in agroecosystems ... [more ▼]

Bacteria are the most abundant and diverse microorganisms in soils. They play an important role in soil formation, contribute to plant nutrition and are involved in various processes in agroecosystems such as nutrient cycling. The aim of this study was to evaluate the impact of the depth on bacterial diversity and quantity in an agricultural soil. Samples was collected on May 2011 and May 2012 at three different depths : 10, 25 and 45 centimeters. The quantity of total bacteria was measured by real time PCR and the analysis of the diversity was performed by the high throughput sequencing technology. Results obtained by these methods show that the biomass and the bacterial quantity and diversity (Shannon index) decrease with the depth, particularly at 45 centimeters. The biomass is, in average, 6.5 fold less important at 45 cm than at 10 cm and the quantity is 17 fold lower at 45 cm than at 10 cm. Our results also indicate that many taxa, such as Betaprotebacteria, Deltaproterobacteria, Gammaproteobacteria, Acidobacteria and Burkholderiales are influenced by the depth. The results will be presented in more details on the poster. [less ▲]

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See detailAn eYFP Reporter Gene for the Yeast Two-hybrid System
Damon, Coralie; Boxus, Mathieu; Twizere, Jean-Claude ULg et al

in Protein Journal (2013), 32(2), 126-130

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See detailRapport scientifique et technique du projet HYDRASANTE (annee 3)
Boudry, Christelle ULg; François, Emmanuelle ULg; Nollevaux, Géraldine et al

Report (2013)

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See detailSymbiont Diversity in Reticulitermes santonensis (Isoptera: Rhinotermitidae): Investigation Strategy Through Proteomics.
Bauwens, Julien ULg; Millet, Catherine ULg; Tarayre, Cédric ULg et al

in Environmental entomology (2013), 42(5), 882-7

The complex microbial community living in the hindgut of lower termites includes prokaryotes, flagellates, yeasts, and filamentous fungi. Many microorganisms are found in the termite gut, but only a few ... [more ▼]

The complex microbial community living in the hindgut of lower termites includes prokaryotes, flagellates, yeasts, and filamentous fungi. Many microorganisms are found in the termite gut, but only a few are thought to be involved in symbiotic association to participate in cellulose digestion. Proteomics provides analyses from both taxonomical and functional perspectives. We aimed to identify symbiont diversity in the gut of Reticulitermes santonensis (Feytaud), via complementary electrospray ionization associated to ion trap tandem mass spectrometry (LC-MS/MS) and two-dimensional gel electrophoresis associated to matrix-assisted laser desorption-ionization-time-of-flight mass spectrometry analysis. One specific challenge to the study of lower termites is the relatively few data available on abundant symbiotic flagellates. Analysis based on LC-MS/MS revealed few protein families showing assignments to eukaryotes and the taxonomic origin of highly represented actins could not be established. Tubulins proved to be the most suitable protein family with which to identify flagellate populations from hindgut samples using LC-MS/MS, compared with other protein families, although this method targeted few prokaryotes in our assay. Similarly, two-dimensional gel electrophoresis associated to matrix-assisted laser desorption-ionization-time-of-flight mass spectrometry did not succeed in identifying flagellate populations, but did permit the identification of most of the prokaryotic components of the symbiotic system. Finally, fungi and yeasts were identified by both methods. Owing to the lack of sequenced genes in flagellates, targeting tubulins for LC-MS/MS could allow fingerprints of flagellate populations to be established. Experimental and technical improvements might increase the efficiency of identification of prokaryotic populations in the near future, based on metaproteomic development. [less ▲]

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See detailRefinement of the production of antigen-specific hen egg yolk antibodies (IgY) intended for passive dietary immunization in animals: A review
Marcq, Christopher ULg; Thewis, André ULg; Portetelle, Daniel ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(3), 483-493

Antibodies have become essential tools in recent decades, with a wide range of applications in the laboratory and in human and veterinary medicine. The use of laying hens, instead of mammals, to obtain ... [more ▼]

Antibodies have become essential tools in recent decades, with a wide range of applications in the laboratory and in human and veterinary medicine. The use of laying hens, instead of mammals, to obtain the necessary antibodies from the eggs is a major advance in terms of animal welfare because it makes blood sampling obsolete. However, the advantages of this technology are numerous, in addition to the animal welfare aspect. With a carefully designed immunization protocol, it is possible to enhance both the hen’s immune response and its welfare during the process. This review puts forward recommendations how to do this and discusses recent approaches on improving the technology. [less ▲]

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See detailInfluence of lignin in Reticulitermes santonensis: symbiotic interations investigated through proteomics
Bauwens, Julien ULg; Tarayre, Cédric ULg; Brasseur, Catherine ULg et al

in Symbiosis (2013)

The gut of lower termites is populated by numerous microbial species belonging to prokaryotes, fungi, yeasts and protists. These micro-organisms are organized in a complex symbiotic system, interacting ... [more ▼]

The gut of lower termites is populated by numerous microbial species belonging to prokaryotes, fungi, yeasts and protists. These micro-organisms are organized in a complex symbiotic system, interacting together and with the insect host. Their likely ability to degrade ligno-cellulosic compounds could lead to improvements in second generation biofuels production. Lignin elimination represents a critical point as this polymer significantly interferes with industrial process of cellulose. Although host produces its own lignin-degrading enzymes, some symbionts may participate in digestion of lignin and its degradation products in termite gut. Here, we compared gut proteomes from R. santonensis after rearing on artificial diets composed of cellulose with and without lignin. The effect of lignin in artificial diets on different parts of the digestive tract was compared through liquid chromatography associated with tandem mass spectrometry (LC-MS/MS) experiments. Enzymatic assays were performed to characterize activities present in R. santonensis digestive tract after feeding on artificial diets. Microscopic observations of microbial communities provided some information on population balances after feeding experiment. [less ▲]

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See detailControl of Salmonella contamination of shell eggs – preharvest and postharvest methods: a review
Galis, Anca; Marcq, Christopher ULg; Marlier, Didier ULg et al

in Comprehensive Reviews in Food Science and Food Safety (2013), 12

Salmonella Enteritidis is one of the most prevalence foodborne pathogen, its most important reservoir being considered the shell egg. As the concerns related to the increasing human salmonellosis cases ... [more ▼]

Salmonella Enteritidis is one of the most prevalence foodborne pathogen, its most important reservoir being considered the shell egg. As the concerns related to the increasing human salmonellosis cases grow, the need for an application of preventive methods either at the farm level or during the processing steps is crucial for a better control of the foodborne outbreaks due to the consumption of this specific food product. This review focuses on the application of preventive methods at the farm level, on preharvest step, in order to reduce the risk of shell eggs contamination with Salmonella, especially S. Enteritidis, through a better control of the laying hens’ infection with this pathogen. As postharvest methods, a first approach is the egg storage conditions and the prevention of Salmonella spp. growth and multiplication. In addition, shell eggs may be subjected to eggshell decontamination, to reduce the risk of foodborne outbreaks. Several of these latter mentioned methods are already authorized to be put in place in different countries, as it is the case in the United States of America and Canada. Their efficacy has been proven and their use is regarded by some as mandatory for ensuring shell eggs safety for the consumers. [less ▲]

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See detailUse of medium without reducing agent for in vitro fermentation studies by bacteria isolated from pig intestine
POELAERT, Christine ULg; Boudry, Christelle ULg; Portetelle, Daniel ULg et al

in Journal of Animal Science (2012, December), 90(Supplement 4), 387-389

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See detailUtilisation des termites comme source de microorganismes dans la filière de production du bioéthanol de seconde génération
Tarayre, Cédric ULg; Bauwens, Julien ULg; Brasseur, Catherine ULg et al

Poster (2012, November 14)

Les termites abritent une microflore symbiotique qui intervient dans la dégradation des fibres constitutives du bois, synthétisant des enzymes capables d’hydrolyser ses composants. Les sucres ... [more ▼]

Les termites abritent une microflore symbiotique qui intervient dans la dégradation des fibres constitutives du bois, synthétisant des enzymes capables d’hydrolyser ses composants. Les sucres fermentescibles libérés suite à cette hydrolyse sont utilisables dans le cadre de la production du bioéthanol de seconde génération. [less ▲]

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